Versatile Pd‐Catalyzed CH Oxidative Cyclization of Homoallylhydrazones to Pyrazolines and Tetrahydropyridazines. Issue 10 (12th July 2013)

• Record Type: Journal Article
• Authors: Mboyi, Cleve Dionel; Abdellah, Ibrahim; Duhayon, Carine; Canac, Yves; Chauvin, Remi
• Is Part Of: ChemCatChem. Volume 5:Issue 10(2013:Oct.)
• Page Start: 3014
• Page End: 3021
• Publication Date: 2013-07-12
• Subjects: Catalysis -- Periodicals; 541.39505
• DOI: 10.1002/cctc.201300220
• Languages: English
• ISSNs: 1867-3880

Abstract

<abstract abstract-type="main" xml:lang="en"> <title>Abstract</title> <p>Pd‐catalyzed 5‐<italic>exo</italic>‐<italic>trig</italic> or 6‐<italic>endo</italic>‐<italic>trig</italic> CH oxidative cyclization of <italic>C</italic>‐homoallyl‐<italic>N</italic>‐sulfonylhydrazones to 5‐vinylpyrazolines or 6‐methylidene‐1, 4, 5, 6‐tetrahydropyridazines, respectively, is shown to be controlled in a highly selective manner by the ionic character of the Pd^II catalytic center. This character is ultimately defined by the nature of the X ligand in the PdX₂ salt serving as an in situ precursor of the active catalytic species involving BIPHIMIP {2‐(diphenylphosphino)‐1‐[2‐(diphenylphosphino)phenyl]‐1<italic>H</italic>‐imidazole} as an optimal spectator diphosphine ligand for both processes. Whereas acetates (X=OAc) favor the 6‐<italic>endo</italic> process, noncoordinating anions such as tosylates and triflates (X=OTs, OTf) favor the 5‐<italic>exo</italic> process.</p> </abstract>